Not All Fingerprint Scanners are Created Equal!

by Sandra Henshaw - , Last Updated on December 15, 2016, How To Guides

Fingerprint scanners are becoming more and more widely available, and even low tier phones are beginning to feature scanners. This seems like a good thing, after all, a fingerprint is unique and has to be more secure than a password or code, right? This is somewhat true, however, a lot depends on what kind of fingerprint scanner we’re talking about. And that’s why we’re here today, to explain all you need to know about scanners so you can know exactly how safe your data is.

The Basics

Okay, in basic terms a fingerprint scanner on your phone works by you registering your fingerprint. The phone saves a copy of what your print looks like, and then the next time you want to open your phone it compares the finger on the scanner with the saved copy of your print that it has. If there’s a match, your phone gets unlocked, if not, then it doesn’t. However, there are three different types of fingerprint scanner, with differing levels of security. If you’re looking into protecting your data with your fingerprint, then it’s important that you know what kind of scanner you’re getting…

Optical Fingerprint Scanners

The oldest kind of scanner tech is known as an optical scanner. This is a simple enough device, and an optical scanner essentially takes a photo of your fingerprint. Of course, a scanner has very high resolution and can take a fairly detailed picture, and the more diodes a scanner has, the more detailed that picture will be. Obviously, more detail is good, since it means added security, there’s less chance of your print being confused with someone else’s.

However, there’s a serious downside to optical scanners, and that is that they’re two dimensional. They take a picture of your fingerprint, and that means that they’re fairly easily fooled. A detailed enough photo of a fingerprint is enough to bypass an optical scanner, meaning they’re not as safe and secure as you may think. However, optical scanners tend only to be used in low end phones these days.

Capacitive Fingerprint Scanners

The vast majority of fingerprint scanners on phones these days are capacitive scanners, and these are a little more complicated to explain. In very basic terms, when you place your finger on a capacitive scanner an electric charge is made wherever your print actually touches the scanner. So where there are ridges on your fingerprint there’s an electrical charge, and where there’s no ridge there’s no charge. This builds up a three dimensional picture of your fingerprint that can be stored for comparison later.

The good part about a capacitive scanner is that it’s much more difficult to fool. Firstly, the fingerprint being scanned needs to be in 3D, so a photograph won’t do the trick. Secondly, different materials conduct electricity in different ways making different levels of electrical charge, which means even making a “fake finger” with a finger print is unlikely to create the identical pattern match that the software is looking for.

In terms of security, capacitive scanners are pretty darn good. However, you do need to be careful of swipe vs. press scanners. Some manufacturers try to save money by having a swipe scanner, which needs less capacitors than a press scanner. Swipe scanners are notoriously fickle and difficult to use, and generally need four or five swipes before they register a print, making press scanners a far better choice.

Ultrasonic Fingerprint Scanners

Ultrasonic scanners aren’t yet widely available on mobiles, but they will become the standard within the next few years due to their high security. An ultrasonic scanner consists of a transmitter and a receiver. When you place your finger on the scanner, an ultrasonic pulse is bounced onto your print, depending on your finger some of that pulse is absorbed and some is bounced back. When the receiver receives the pulse message it translates that into a full three dimensional picture of your fingerprint, making it very, very difficult to fool indeed.

Sadly, you’re not likely to see an ultrasonic scanner on shelves for a while yet, but once they become available this is the top choice for ultimate phone security.

Other Concerns

A fingerprint scanner takes a digital picture of your print and stores it, so your last concern when looking at scanners is cryptography. You don’t want that copy of your print getting out, since it could then technically be used to unlock your data, and that’s why many fingerprint scanning programmes encrypt their data. At the moment it’s difficult to tell how well, or even if, your print is encrypted, although Qualcomm scanner software does always encrypt. But as we come to depend on our fingerprints for more and more things, particularly activities like digital payment systems, then this encryption tech is going to become a lot more important. In the future, stealing someone’s fingerprint could be the same as stealing someone’s credit card is now.

What You Want

The bottom line here is if you’re looking for a phone that offers the security of a fingerprint scanner to protect your data then you’re going to need to choose carefully. You’re looking for a capacitive scanner that is press to scan, not swipe to scan. And for the most part, that’s going to mean investing in an upper end phone that’s going to cost you a fair bit of cash.

Whilst lower end, and cheaper, phones do sometimes offer fingerprint scanners, it’s unlikely that these models are going to offer you the level of security that you’re really looking for. And as scanners become more popular, they’re going to become more of a focus for hackers. Just as with passwords and codes, it’s only a matter of time before someone smart and unscrupulous figures out a fast way to bypass a fingerprint scanner. And if that’s the case, then you want the best scanner you can get, and you want encrypted data.